Related-art image forming apparatuses, such as copiers, facsimile machines, printers, or multifunction printers having at least one of copying, printing, scanning, and facsimile functions, typically form an image on a recording medium according to image data. Thus, for example, a charger uniformly charges a surface of an image bearing member; an optical writer projects a light beam onto the charged surface of the image bearing member to form an electrostatic latent image on the image bearing member according to the image data; a developing device supplies toner to the electrostatic latent image formed on the image bearing member to render the electrostatic latent image visible as a toner image; the toner image is directly transferred from the image bearing member onto a recording medium or is indirectly transferred from the image bearing member onto a recording medium via an intermediate transfer member; a cleaning device then cleans the surface of the image carrier after the toner image is transferred from the image carrier onto the recording medium; finally, a fixing device applies heat and pressure to the recording medium bearing the unfixed toner image to fix the unfixed toner image on the recording medium, thus forming the image on the recording medium.
During image forming operation, the internal temperature of the image forming apparatus rises. In order to prevent overheating of devices in the image forming apparatus, a cooling device such as a fan is provided to the image forming apparatus.
In a known approach, the cooling device is activated when the number of scanned pages or printed pages or cumulative image forming time reaches a threshold value. Typically, after the image forming operation, the cooling device is stopped.
However, after an extended period of continuous operation of the image forming apparatus, the temperature of the developing device employed in the image forming apparatus rises, causing toner in the developing device to melt prematurely and hence degrading imaging quality. Moreover, because the temperature of the developing device is difficult to detect directly it continues to rise if left unchecked.
In order to cool the developing device, the cooling device may be operated continuously even after image forming operation ends. Although effective, continuous operation of the cooling device increases power consumption and produces noise, complicating efforts to reduce power consumption as is usually desired.